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The Method of Testing The Presence Of Arsenic


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The Method of Testing The Presence Of Arsenic

  1. 1. Learning The Method of Testing The Presence Of Arsenic Arsenic measurement :1.Certain amount ofsample taken 6.A Mercury strip inserted. Arsene gas reacts2.KI (Potassium iodide) with Hg.added to the sample. 7. Reaction takes about 203. 1 tablespoon of Zinc min.compound powder added.4. The container is shaken 8.Colour obtained can bewell. matched with data provided.5. Colour changes frompurple to grey . 9. The standard level is 1ppm
  2. 2. ANALYSIS OF WATER Portable kit is used:  Sample: fresh water body….(stagnant water)  pH-6.5-8.5 , conductivity- 553uS/cm,  Salinity- 0  Dissolved Oxygen- >4
  3. 3. Ion Selective Electrode (ISE): Lanthanum crystal probe to test concentration of fluoride ion. 10 ml of solution containing fluoride ion taken. 10 ml Total Ionising Strength Adjustable Buffer (TISA) added. Thus, they are in 1:1 ratio. 1.5ppm is considered within safe levels. In west Bengal there is a high fluorite level in Baruipur , Sonarpur, Thakurpukur areas.
  4. 4. Ion selective Electrode Probe for fluorideion detection- •10 ml of sample is taken. Lanthanum crystal electrode used…. • TISAB( Total Ionising Strength Adjustable Buffer) is used •Result- F-1 present – 0.379 mg/l
  5. 5. ARSENIC DETECTION •Procedure- KI is added to sample of contaminated water- colour changes from colourless to purple. •Zn added --- changes arsenic from pentavalent to trivalent •Compound of Zinc added ----- colour changes to grey • Mercuric chloride paper held above but the solution must not touch it •If arsine gas come in contact with the paper gas turns to mercuric arsenate after 20 min black colour would be seen. Experiment performed by the students in the chemistry laboratory at Geological Survey of India(GSI)
  6. 6. Arsenic test kit Black colouration here indicates that the sample contains arsenic.
  7. 7. Handling the portable kit probePortable Kit Probe As dissolved If less than is used to oxygen levels 4, then measure, H+ in water drop water is conductivity, below 5.0 mg/l, considered For potable salinity, Mg and aquatic life is to be water pH Ca ion content, put under stagnating. value lies stress. between 6.5 to 8.5 Dissolvedoxygen, arsenic For potable For potable water D.O. is water content and conductivity is other around 5.18 less than 1000. mg/l. properties of water sample.
  8. 8. Total hardness: Ca and Mg ions contribute to hardness The value obtained 10 ml of sample is the total taken. hardness value. 2 drops of The colour changes Eriochrome Black T from pink to light (EBT) indictor blue. added. NH4Cl (buffer NH4OH added. solution) added dropwise.
  9. 9. Total Hardness Titration Method:- In burette EDTA is taken •The sample is taken in dish. •2 drops of EBT indicator is added….Buffer is mixed…………… •Observation- colour changes from pink to blue . Hence Mg +2 and Ca+2 are present…..
  10. 10. This a short As If we start our Water is an survey that we students, this is mission of inevitable students had the most protecting our source of conducted…. important mother Earthlife… being May not be a approach in right from children of huge one…but order to now…..then mother earth we have been prevent futurewe must never taught that the mankind from generations will destroy this many little steps committing sins be able to livevibrant heritage of ‘me’ will prove like causing in harmony with of her’s. to be the giant water pollution. the nature… leap of ‘us’ ….
  11. 11. Thank you…By B.D.M.International